Tobacco treatment process



Oct. 15, 1940. 4 H, 1 '.sMrrl-LJR.. Er A1, 2,217,935 l Filednec. 21. 1957 s sheets-sheet' i ATTORNEYS? H. L. SMITH. JR.. ET AL TOBACCO l' TREA'MENT PROCESS Filed nec. 21, 1937 y 5 Smets-sheet 2 lf. -INVENIZORS- ATTO RNEYS oct; 15,V 1940. H, L; SMH, JR., M 2,211,935

TOBACCO TREATMENT PROCESS Filed uw. 21. 1,937` s `sneetsr-imm s ATTORNEYS Y Patented Oct. 15, 1940v 2,217,935 y To'B'Acco TREATMENT Pnocitss Horace L. Smitln'Jr., and Lucian N. Jones, vlticlimond, Va., assignors, by mesne assignments, to

The Guai-dite Corporation, Chicago, Ill.,

poration of Illinois a corl Application December 2l, 1937, Serial No. 180,987

1 Claim.

This invention relates to tobacco treatment and more particularly concerns an improved process for altering" the moisture content of and* application, Serial Nol 54,443, filed December 14, 1935, .the tobacco is successively subjected to a highvacuum, supplied with steam with a reduction in ldegree of vacuum, and again subjected to a relatively high vacuum with the result that the moisture content vof the ltobacco is quickly increased without undesirable discoloration or other deterioration of the tobacco. The successive' steaming and re-evacuating steps may obviously `be repeated one ormoretlmes if desired. As disclosed m our patent above referred to, this process is also effective in exterminating organisms which infest tobacco.

It is the general object. of the present invention to provide an improved, process embodying the basic features of our aforesaid process, and to provide improved apparatus which may be used in carrying out these and related processes. We have found that. moisture can be supplied to tobacco more effectively and in larger quantities by modifying our aforesaid process as hereinafter explained.A 'I'he improved process is particularly luseful in the treatment of tobacco which is. tightly packed in hogsheads, -bales or the like, and may 40 also be used Yinthetreatment of loose tobacco.

v Like vthe original process, the improved process v is effective in exterminating pests which infest tobacco in all forms of their life cycle.

. According to one feature of the present inven-j 45' tion, steam is maintained in contact with the tobacco at a substantially constant pressure for a time interval after the absolute pressure on the tobacco has been increased from a relatively high vacuum Y value by the steam supplied thereto. Thisomay be conveniently accomplished by continuouslysupplying steam; with or without water, as hereinafter explained, to the tobacco at a low rate sufficient to substantially replace the steam being condensed in the tobacco structure. This our PatentNo. 2,086,446,`and in our-copending vtobacco structure thereby.

(c1. isi- 140) pressure preferably characterizes each steaming step regardless of whether one or more steaming steps are involved.

`.A still further feature of our present invention is supplying both water and steam tothe tobacco, the water preferably taking the form of a fine mist or spray entrained in the steam andinjected therewith intothe evacuated'space containing the tobacco. When' steam under pressure is introduced to apreviously evacuated area, the re. duction in pressure, unaccompanied by theperformance of work, liberate's heat, which results in superheating ofthe steam., The water introduced with the ste'amV is vaporized, the superheat of the steamv supplying the necessary latent heat .of vaporization. The steam is thus de-'sup'erheated with the result that unnecessary heating of the tobacco by the steam is avoided. We prefer to introduce with the steam an amount of water considerably in excess -to that necessary to de'- superheat the steani at the reduced pressure, whereby excess water, preferably in the form of a fine spray, suspension or mist, is entrained with y the steam and carried into contact with the This is preferably accomplished by breaking up or atomizing a stream of water within or substantially within the previously evacuated treatment chamber at or adjacent the point where the steam is introduced thereto. Other ways of introducing steam and water may be employed, but we believe that the method generally described is preferable be-f.

steam and water into apreviously evacuated treatment chamber in such a manner that the steam is de-superheated and excess water is formed into a line, suspension or mist and introduced with-the -steam and carried thereby into intimate contact with the tobacco or other ma-v terial in the chamber. In a preferred embodi-l ment, this'j'ineans includes a'nozzle structure having therein means for directing a stream of water under pressure into impinging contact with a surface whereby the water is broken into a mist in. the presence of the steam.I 'lhe structure preferably directs the steam adjacent the point of impingement of the water stream', whereby the stream assists in atomizing the water and en- 'trains the water mist (or the proportion thereof which has not immediately vaporized in de-superheating the steam), and sweeps it out of the nozzle opening into the treatment chamber, In one form of the invention, the nozzle structure is so constructed and mounted with relation to a tobacco treatment chamber that impingement of the stream of steam and entrained water against the chamber walls is minimized. This prevents considerable loss of entrained water in the introduced uid prior to its contact with the tobacco of other material under treatment.

Other objects,'advantages and characteristics of our invention will be apparent as .the description thereof progresses.

In describing the invention Yin detail, reference will be made to `the accompanying drawings, in which;

Figure 1 is a diagrammatic and simplified illustration of apparatus capable of carrying out our improved process;

Figure 2 is a sectional view of improved steam and water injecting apparatus embodying certain features of our invention; and

Figure 3 is a graph illustrating the various steps to which tobacco may be subjected in a typical treatment cycle embodying certain features of our invention.

Various forms of apparatus may be employed in carryingoutfour improved process. The ill lustrative apparatus diagram, shown in Figure 1, includes a pair of tobacco chambers 4 and 4' of substantially identical construction. The two chambers are employed to permit the loading of one at the same time that tobacco is being treated in` the other. The process could obviously be carried out in a single chamber. The chambers shown are cylindrical and are provided with removable doors or closures 5 and 5 at each end thereof to permit the introduction and removal of the tobacco to be treated. Since our process involves subjecting the tobacco to a high vacuum, the treatment chambers 4 and 4' are air tight and the doors 5 and 5 are provided with suitable gaskets or other sealing means which prevent the admission of air while a process is being carried out. Each chamber 4 and 4 is preferably large enough to accommodate several hogsheads of tobacco and suitable means may be provided for introducing the hogsheads and removing them from the chambers. Suitable means are .provided for selectively evacuating or drawing uid from the chambers 4 and' 4'. Althoughvarious means may be used for this purpose, 'we generally prefer to employmulti-stage steam jet evacuators which we have found to give excellent results. The

illustrated apparatus includes a three-stage steam jet evacuating system but a greater or smaller number of stages ymay be used where warrantedby the conditions encountered.

As shown, the chambers 4 and 4 are respecl tively connected through the suction line valves i and I with a common T fitting 1 opening into the'inlet of a first stage steam Jet.ejectoror booster I., The first steam jet booster l discharges through a pipe l into an inter-condenser i l. The intercondenser Il may take any mutable form, and as shown, oomprisesa direct contact condenser of4 knownY construction. 'I'he intercondenser Il is vsupplied, with' waterV through a pipe I I under control of the valve I2. Water and condensate are withdrawn from the intercondenser I through a pump Il constructed to prevent the ingress of air to the condenser. rIhe fluid outlet of the intercondenser I0 is connected to the inlet of a secondstage steam Jet ejector I4 which discharges into a second intercondenser I5. The intercondenser I may be similar in construction to the ilrst stage intercondenser I0, but is preferably of smaller capacity. Water is supplied to the' intercondenser I5 from the pipe I I undercontrol of a valve I6, and condensate and water are withdrawn by a sealing pump I1. Two third-stage steam jet ejectors I8 and I8' are connected in parallel to withdraw fluid from the second intercondenser I5. The ejectors I8 and I8 may discharge steam and evacuated duid to the atmosphere directly through an exhaust pipe I9, or a final condenser may be employed to condense the exhaust steam, if desired. A trapped drain 2D is preferably provided to carry off the liquid which condenses inthe exhaust pipe I9, and theA liquid from this drain may be either wasted or recirculated through a cooling system be connected. The rst stage steam booster B receives steam through a branch pipe 22' under the controlof an automatic valve 23 and a hand valve 23. The second and thirdstage` electors receive ysteam from the pipe 24. The automatic valve25 and manual valve 25' govern the ad- *missionA of steam to the vsecond sta'ge ejector I4 and the automatic valve 26 andmanual valve 2B' control the admission of steam to the third stage ejector I8 and I8 in parallel.

Suitable means are provided for admitting steam to the treatment chambers 4 and 4'. In the disclosed embodiment, steam is introducedat a plurality of points' spaced longitudinally by means of the manifold pipes 21 and 21' and the branch pipes 28 and 28' which terminate in openings in the chamber walls. The manifold pipes 21 and 21 are connected to the steam supply pipe 2| through automatic control valves 29 `and 29', and manual valves 30 and 3U may also be used at this point, as shown. Restricted by-pass pipes Il and'll' are preferably connected-respectively around the automatic steam control valves 29 and. 29' to admit steam at a restricted rate to the chambers 4 and 4' at certain times, as hereinafter explained. Water may be introduced with the restricted steam supply if desired. Automatic control valves 22 and 32` ychambers with steam, and for. this purpose, water manifold pipes 23 and 22', each having branch pipes 34 and 34', are provided for the respective chambers 4 and 4'. [The branch pipes I4 and I4' areV connected to spaced openings in the walls of the chambers 4 and# respectively, and preferably enter these chambers at the same points as the branch steam pipes 2l and 2l'. The adg.V mission of Vwater is controlled by the automatic valves 4l and 4l' in the manifold pipes 2l and u' respectively and manually Operable valves In and 5l' may also be provided for this purpo.

, enter .the chamber.

from the pipel 28 ows through the openings 45 Suitable means are provided for venting the chambers 4 and 4' to the atmosphere. As shown, the pipes and 35', controlled respectively by the valves 36 and 36', are used for this purpose.y

and evacuation of the chambers, may be controlled manually by separate valves,v manually from a central point or by suitable `automatic control apparatus. The .particular form of control valve actuation employed forms no part of the Apresent invention but in many instances both manually operable and automatic valves have been disclosed to indicate the dierent types of y actuation which may be resorted to. 'I'he suction line controlled valves 6 and 6 are preferably of large capacity and are usually operated by diaphragm or electric means of known construction. The remaining automatic valves may be similarly operated.

In accordance withk one feature of our invention, water is introduced to the treatment chambers with the steam during the steaming steps or stages including the soaking stage if desired, and is converted into a fine mist or suspension and entrained with the steam as the two uids We have devised an improved apparatus `for performing this function and it is illustrated in Figure '2. In this figure, the wall of a treatment chamber is illustrated at 4, a steam supply pipe at 28 and a water supply pipe at 34. 'I'hese parts may comprise the' nected through a nipple 39 and a T` tting 40. to the steam supply pipe 28, and the water supply pipe 34 passes axially throughthe parts 38 and 39 and issealed in an opening of the T fitting 40 by a suitable packed gland 4I. The end of the Water pipe is xed to a water nozzle fitting 42 in communication with a central water passage 43 of small bore which terminates in a nozzle opening 44; The fitting 42 is threadedly connected within the inlet bushing` 31 and is proi vided with a plurality of steam openings 45 disposed about the central water passage 43. AA

deflecting disc D is fixed in spaced relation to the inner end of the fitting 31 by suitable means such as the bolts-41. The disc D extendsacross the outlet of the fitting 31 and preferably comprisesa plane circular central portion 48l surrounded by a frusto conical or tapered rim portion l49. The discD cooperates with the limer end of the ntting 31 to form a iiuid outlet nozzle which directs the discharged fluid outwardly substantially parallel to the wall-of the treatment chamber.

Water is suppliedthrough the pipe 34 at a relatively high pressure and accordingly issues from the water nozzle 44 in a fine stream at high velocity and impinges upon the plane central `portion 4,8 of the disc I D where it is broken up into a fine mist orsuspension. 'I'he steam l chamber in inches of mercury, and the abscissa toward the disc D, and aids in breaking up the water into fine particles. The contact between the water and steam at the reduced pressure within the treatment chamber results in the 5,

vaporization of' some1 of the Water with a resultant de-superheating of the steam, and the yexcess water over that 'thus vaporized is entrained by the steam and carried out through the nozzle opening formed by the disc D and the 10 fitting 31. Since. the nozzle opening directs the injected fluid in an initial path substantially parallel to the treatment chamber Wall, the loss of water from this rfluid by impinging contact against the chamber wall at high velocity is 15 minimized. After curing, tobacco is customarily tightly packed in hogsheads, bales or the like and is aged in warehouses for periods which may run lto sev- ',eral years. The tobacco loses moisture during20 aging and as a result becomes so dry and brittle that it cannot be unpacked, .much less handled or stemmed, without excessive loss from shattering, tearing or powdering of the leaf structure. The process of `the present invention Vmay be`em- 25 ployed to increase the moisture content at various stages during the preparation or shipment of tobacco, and also to exterminate organisms inltobacco with or without alteringv its moisture content. The process has proven particularly effective in the so-called ordering of aged and relatively drypacked tobacco', that is, increasing the moisture content of such tobacco to a point where it can be unpacked and stemmed without substantial breakage of the leaf structure. Our process will be here described byreference to a typical example thereof as employed in ordering tobacco.

The tobacco, which is usually packed in hogsheads `or bales, is placed within one of the treatl ment chambers, for example, the chamber 4. The heads may be removed fromv the hogsheads before treatment if desired, but this operation is not essential since `tobacco hogsheads are not iiuid tight. The doors 5 ofthe treatment cham- 45 ber 4 are closed and the tobacco is subjected to a series of operations which have been graphif cally illustrated in Figure 3, where the ordinates represent absolute pressure in the treatment represent time in minutes.

The tobacco vin the treatment chamber 4 is first subjected to a relatively high vacuum, as indicated by the portion abcd of the `curve in Figure 3. Thel degree of vacuum should be such as to remove substantially all of the air initially contained in the treatment chamber and the interstices of thestructure of the tobacco therein. We have found that ther degree of vacuum required for this purpose varies somewhat with the temperature of the tobacco. Thus with tobacco having an initial minimum temperature of about '70 F..or higher, a vacuum from 29.5 to 29.6 inches of mercury (.5` to, .4 inch Hg absolute pressure) l is suiiicient, whereas with lower initial minimum temperatures of the tobacco mass, yvacuums as high as 29.85 to 29`.9or even higher may berequired. In the example illustrated in Figure 3, the initial minimum temper-` ature of the tobacco mass is assumed vto be in the neighborhood of 70 F., and the initial `Vacuum isdrawn to about 29.65 inches 'of mercury (.35 inch of Hg absolute pressure).

The steam Jet evacuating equipment described may be operated in various ways to produce the and economical. The suction line valve I is opened and the valve 6' controlling the chamber 4 is closed, the valves 36. 23, i2, 25, li, 2l, 32 l and I6 being closed. The steam supply valve 26 for the third stage electors I8 and Il'is opened and these ejectors, acting in parallel, reduce the absolute pressure byl withdrawing fluid from the treatment chamber 4 as indicated by the portion ab of the curve abcelin Figure 3. At about the point b, it is preferred to start the second stage ejector I4 and this is done by opening the steam valve 25. At the same time, cooling water is admitted to the second intercondenser i by opening the water valve Il, and in this manner, the steam issuing from the ejector I4 is condensed before lt reaches the third vstage ejectors I8 and I8'. When the absolute pressure of the ,chamber has been further reduced toa value such as that indicated by the point c on the curve, the first stage booster 8 and first intercondenser Il! are operated by opening the steam valve 23 and the water valve l2. With all of the ejectors in operation, the absolute pressure on the tobaccois rapidly reduced to the desired final value, as indicated by the point d in Figure 3. As shown in Figure 3. theentire evacuating operation can be completed in a relatively short interval, less than twelve minutes in the illustrative example shown. At the conclusion of the initial evacuating step, the suction line valve is closed 'and the electors and intercondensers are shut down by closing the valves 23, l2, 25,v I6 and 26. 1

After the desired high vacuum has been attained, steam is supplied to the tobacco whereby the vacuum thereon is reduced. In accordance withone feature of our invention, 4water issupplied to the tobacco simultaneously withthe steam, the amount of water so supplied beingV plierie value. We believe that the excess water.

introduced is carried into intimate contact with the tobacco by the steam which ilowsrapidly into the previously evacuated tobacco structure. In this manner, the moisture content of the tobacco is increased, both by the condensation of steam and by the water introduced with the steam.

During thesteaming step, the absolute pressure should be increased to such a value that the steam, and entrained water where water is introduced therewith, will quickly penetrate the tobacco mass and moisten it substantially uniformly throughout. 'I'he steam introduced heats the tobacco and raises its temperature, and the amount of steam introduced, as determined by the abwlute pressure attained at the' ,conclusion of the steaming step, should not be so high as to cause discoloration or other heat deterioration of the tobacco within the time interval during which the elevated temperature is maintained. In accordance with our process, the absolute pressure attained in the steaming step produces atobacco temperature high enough to cause discoloration of the tobacco after a time interval,

but prior to the expiration of such interval, the

absolute pressure is reduced sumciently to' vaptobacoo structure by the steam.

vbe used. i In a typical example of our process,

'may be Aintroduced with the steam through each nozzle illustrated in Figure 2 and described above preciably lower the tobacco temperature, whereby discoloration or other heat deterioration is avoided. This reduction of absolute pressure takesplace in the re-evacuating step'or steps as hereinafter described. In the example disclosed 5 in Figure 3, it is assumed that bright tobacco is under treatment, and the absolute pressure at the end of the. steaming step is about ten inches of mercury (a vacuum of about 20 inches of mercury). WhenI the process is applied to burley tobacco, which is more resistant to heat than bright tobacco, the absolute pressure at the end of the steaming step may reach a value in the neighborhood of 12 inches of mercury (a vacuum of 18 inches of mercury). With various varieties of tobacco and times of treatment, the nal steaming pressure may vary between about 8 and 18 inches of mercury absolute. The steaming step is terminated by 'closing thesteam and water valves l! and Il. 20

The amount of water introduced during the steaming step is preferably in excess of that required to de-superheat the steam supplied to the tobacco whereby an excess of water, in the form of a une mist` or suspension, is carried into the The amount of water so` introduced is not critical, and amounts from twice to four or five times the amount necessary to de-superheat the steam may assuming that 25 lbs. per minute of dry saturated steam at an initial pressure of about 115 lbs. per square inch gauge is introduced through each branch pipe 2l, about .7 gal. of water per minute branch pipe 34. In the example given, assuming an initial vacuum of about 29.5 inches of mercury in the chamber, approximately .35 gal. per minute of water would be sufficient to saturate (de-superheat) the steam introduced at each branch pipe.

'Ihe water is preferably introduced to the tobacco chamber at the same point as the steam whereby the steam is de-superheated as the superheat develops and the water is broken up and entrained by the steam as it enters the chamber. I'he atomizing or breaking up of the water may be promoted by the use of known types of atomizing or spray nozzles, or the improved may be employed for this purpe. One or more combined water and steam inlets may be provided, and good results are obtained by using one such inlet for -each hogshead, bale or other mass of tobacco in the treatment chamber l. When our improved steam and water. injecting nozzle is used, one such device may beprovlded at each inlet point and located' adjacent each tobacco hogshead. l

A so-called soaking step preferably follows the introduction of steam and water. During this portion of the process, the absolute pressure on the tobacco is maintained constant or nearly constant for a limited timeinterval as indicated oy the portion el of the curve of Figure 3. The previously introduced steam continues to condense after the introduction of steam has been discontinued, and accordingly, the pressure in the chamber I would normally fall during the "soaking period. Accordingly. weprefer to introduce steam at a' low rate substantially sumclent to continuously replace the steam being condensed, whereby the absolute pressure on the tobacco is maintained substantially constant. This may be accomplished by opening the steam valve I2 in 15 the restricted by-pass pipe 3 I it being understood that the rate of steam ow through this pipe is reduced by the'ppe size, a restricted orifice or otherwise to produce the desired continuous replacement of the steam being condensed in the chamber. 'I'he introduction of steam at a restricted rate during the soaking stage may, if necessary or desirable, be accompanied by the introduction of water in the form and amounts explained above. minated by closing the valve 32.l

At the conclusion of the soalnngstep, the tobacco is subjected to an increased vacuum, the pressure thereon being reduced as indicated by the portion fg of the curve in Figure 3. The degree of evacuation to which th tobacco is'subjected in thisstep is preferably high enough to vaporize or evaporate some moisture from the tobacco whereby its temperature is reduced, heat being absorbed in the form of latent heat'of vat porization. This re-evacuating step may comprise the nal step of the process, andthe evacuation preferably continuesto an absolute pressure or vaporized to reduce the tobacco temperature to a safe value. The heat discoloration and other heat deterioration of tobacco is a function of the temperature, the time for which the temperature is maintained and the type of tobacco under treatment. If certain types 'bf bright tobacco are maintained at temperatures above about 125 F. for an extended time interval, discoloration and often other forms of heat deterioration take place,

and the value of the tobacco is thereby substantially reduced. However, these tobaccos may bemaintained at temperatures in the neighborhood of about-l80 F. for intervals of about 10 or 15 minutes without discoloration or other detrimental change. In general, bright tobacco is more` sensitive to heat than other varieties,burley tobacco, for example, will withstand high temperatures for appreciably longer periods than will bright tobacco.

The re-evacuating step fg of our process is continued to a value of vacuum at which the temperature of the tobacco has been reduced by the evaporation or vaporization of moisture to a value at which heat deterioration wlllnot take place. This temperature, and, accordingly, the iinal value of vacuum, varies as indicated above depending upon the type of tobacco under treatment. The treatmentto which the tobacco is subjected after the conclusion of our process is also a factor in xing the i-lnal tobacco temperature. In most cases, the tobacco is unpacked from the hogsheads or bales and the leaves are separated immediately after the ordering treatment. With this procedure, the tobacco is cooled by the atmosphere promptly after the treatment process is concluded and accordingly the temperaturev to which the tobacco is reduced in the re-evacuating step may be somewhat above the minimum temperature at which heat deterioration can take place after an extended interval. If the tobacco is not-.to be unpacked at the conclusion of the rocess, the re-evacuation is continued until the tobacco temperature is below the lowest temperature at which'it can be adverseiyeected by heat in any time interval.

In the disclosed example, assuming bright tobacco is under treatment and is to be unpacked at the conclusion of the process, the re-evacuating step fg is continued to a vacuum of about 27.25 inches of mercury (2.25 inches of mercury absolute pressure). This nal vacuum may vary from 'I'he soaking step is terabout 25 to about 29.8 inches of mercury (5 to .2 inch of mercury absolute pressure) and in the case of very dark heat resistanttobaccos, whichl are to be unpacked immediately after treatment, the nal vacuumrmay be as low as 20 inches of mercury (10 inches of mercury absolute pressure).

The re-evacuating step fg may be performed by operating the third stage ejectors I8, I8 and the rst stage intercondenser I0 until thev absolutepressure has been reduced to some-intermediate point, such as the point k, TheV second stageejector` I 4 and second intercondenser -I5 may then be operated by opening the valves'25 and I6 and the absolute pressure is further reduced to the point g by the second and third stage ejectors acting in series. If desirable orrnecessary, the rst stage booster 8 may also be operated in drawing the desired vacuum. 1 The revevacuation step is concluded by closing the suction line valve`6 and cutting off the supply of steam and Water to the ejectors and intercondensers. i

VAt the conclusion of the re-eyacuating step fg, the treatment chamber 4 is vented by opening the valve 36, and the pressure on the tobacco rises to atmospheric pressure as indicated by the curve section gh. The tobacco is now removed from the treatment chamber l and the process is complete. Y

It is obvious that the above described steaming and re-evacuating steps may be repeated one or more times if desired. One such repetition has been illustrated-by the broken line curves starting lat the point g'in Figure 3. Since a second steaming, soaking and re-evacuating cycle consumes only a short time interval, `the temperature to which the tobacco is cooled in the first re-evacuating step may be somewhat' higher thanthe temperature required at the conclusionf of the treatment. Thus, as shown in Figure 3, the first re-evacuating step may continue until the absolute pressure is reduced to' about 4 inches of mercury '(a vacuum of. 26 inches of mercury). In general, a practical working range of absolute pressures 'at the conclusion of an initialre-evacuating step may be from about 3 to about l5 inches of mercury absolute.

The rst re-evacuating step in the case of recycling may be accomplished by manipulating the apparatus as described above. It is usually necessary to operate the third stage ejectors I8 and I8' and the rst intercondenser II) only, although operation of the second stage ejector I4 and second intercondenser I5 may be resorted to during a part of the re-evacuatinggstep, if necessary or desirable.

The re-evacuating step just described is followed successively by a repetition of the steaming, soaking Y and re-ev'acuating steps. The

Amanipulating the apparatusas described above inconnection with the steaming, "soaking" and re-evacuating steps represented by the curve secgh' is usually of shorter duration than the rst steaming step de, the absolute pressure on the .tobacco at g being somewhat higher than that 1 tions de, ef and fg. -The second steaming step at d, and the final steaming or soaking pressures being substantially the same in each case. At the end of y the'nal re-evacuating step jlc'l, the treatment chamber is vented to the atmosphere, as indicated by the line lm, and the tobacco is removed from the chamber. The soaking step is believed to .aid in the uniform distribution of moisture in the tobacco. By intro- .ducing water with the steam, the amount of moisture added'to the tobacco is increased without undesirabiy increasing the maximum temperature to which the tobacco is heated.

Our improved .process exterminates tobacco l0 pests, such as the cigarette beetle', in all forms of its life cycle. This can be done simultaneously with the addition of moisture as described above. or without net change in the moisture content. In the latter case, the re-evacuating step is conitinued' untilail of the added moisture has been L"evaporated or vaporized and removed.

It should be understood that the described examples are merely illustrative and that our invention is not limited to the=values of pressure and vacuum or the time intervals set forth above and indicated in Figure 3. The various features of our invention may be separately employed.

Although the process of the present invention has been described in connection with an exam- 'ple of its applicationto the moistening or ordering of packed and aged tobacco, it should be understood that the invention'is not limited to this application and maybe applied to other steps in the treatment of tobacco or other materials where it may be found applicable. For example,

'we have found that ourjabove described process is eiective in destroying mold and mold spores which sometimes appearsin aged tobacco. We have also found that our process is eiective in 4tempering and improving the, quality of cased tobacco, that is, tobacco to which iiavoring ma terials, have been added. In either the destruction of mold or mold spores or the tempering of cased tobacco, our process may be so conducted as to increase the moisture content of the tobacco or without net change in the moisture content, and in the latter case, the re-evacuation iscontinued untill all or substantially all of the added the steam and water are impacted and thoroughly intermingled and water in a. 4tine spray is produced, and supplying the reected steam and Water to the tobacco whereby the moisture content thereof is increased.

HORACE L. SMITH, Ja. LUCIAN N. JONES.

` to the point of entrance of the streams, whereby l 

